1. Field of the Invention
The present invention relates to a method for producing silicon. More particularly, it relates to a method for producing silicon, whereby silicon can be produced at a very low cost and at a high production rate as compared with conventional methods.
2. Description of the Prior Art
Heretofore, the so-called Siemens method has been known for the production of silicon, wherein a slender silicon rod is disposed in a bell-shaped container, the interior of the container is flushed with pure hydrogen, and trichlorosilane diluted with H.sub.2 is supplied while maintaining the rod at a temperature of from 1050.degree. to 1150.degree. C. by an application of electricity, whereby silicon is precipitated and formed on the surface of the slender silicon rod at a high temperature. This method has an excellent feature that it is thereby possible to produce highly pure silicon with a purity of at least 99.999999%. However, this method had the drawbacks that not only is the growing speed of silicon is slow, but also a great amount of electric power (from 100 to 200 kwh to obtain 1 kg of the product) is required, whereby the production cost is very high. Accordingly, it would be desirable to develop a method for producing silicon having a high purity without consuming electric power.
As one of the methods for producing silicon without using any electric power, a method has recently been proposed which comprises introducing hydrogen and chlorine gas into a reactor, burning them to generate a flame, blowing silane or a halogenated silane into the flame to let it undergo thermal decomposition and precipitating silicon on a seed material which is rotated (Japanese Examined Patent Publication No. 17843/1982). According to this method, it is necessary to generate a flame by means of chlorine and hydrogen.